A cross-sectional study was conducted with individuals of both sexes (20-59 years of age), all covered by the COOPERSINOS Health Care Plan of Vale do Rio dos Sinos University. The study aimed to determine the prevalence of lower back pain and associated factors in the previous three months. A self-applied questionnaire included socioeconomic, demographic, occupational, and lifestyle questions. Prevalence of lower back pain among the 775 individuals was 52.8% in the previous year (95%CI: 49.3-56.3) and 46% in the previous three months (95%CI: 42.5-49.5). Poisson regression for lower back pain in the previous 90 days showed an association with: (1) age 40-49 years; (2) self-reported strenuous or difficult work; and (3) smoking. Despite the high prevalence of lower back pain and difficulty in performing work activities, the pain was not disabling. Although 29.9% of workers reported some difficulty in performing their daily or work-related activities due to lower back pain, absenteeism was quite low.